1. Technical Field
The present invention relates to an electro-optic device, a method of manufacturing the electro-optic device, and an electronic apparatus.
2. Related Art
Electro-optic devices are known in which an element substrate in which optical elements such as light-emitting elements or light-receiving elements are disposed and a counter substrate facing to the surface of the element substrate on which the optical elements are disposed are bonded (for example, see JP-A-2008-59868). In the electro-optic device (organic EL device) disclosed in JP-A-2008-59868, an element substrate and a counter substrate (sealing substrate) are bonded via a sealing member disposed on the outside of a region in which light-emitting elements are disposed. The inside surrounded by the sealing member is filled with a resin material (filling layer) to alleviate stress, impact, or the like applied from the outside. Thus, it is possible to prevent the counter substrate from being deformed when the inside of the sealing member is hollow (air layer) or prevent light from being reflected from an interface between the counter substrate and the air layer.
In the electro-optic device disclosed in JP-A-2008-59868, however, since the sealing member is disposed on the outside of the region in which the light-emitting elements are disposed, there is a problem that a region (so-called frame region) on the outside of the region (light emission region) in which the light-emitting elements are disposed increases in size in the entire region on the element substrate. Also, there is a problem that the resin material filling the inside of the sealing member protrudes to the outside of the sealing member when one substrate is pressed against the other substrate, or curving or distortion occurs in the element substrate or the counter substrate since the thickness of the sealing member and the thickness of the resin material become non-uniform due to contraction (volume variation) when the resin material is hardened.
On the other hand, an electro-optic device in which an element substrate and a counter substrate are bonded without a sealing member has been suggested (for example, see JP-A-2007-157606). In the electro-optic device (light-emitting device) disclosed in JP-A-2007-157606, the element substrate and the counter substrate (surface protection substrate) are bonded by applying a resin material (adhesive layer) to light-emitting elements by a screen printing method or a slit coating method. The resin material (adhesive layer) has a function of adhering and fixing the counter substrate to the light-emitting elements and a function of alleviating external stress or impact. When such a configuration is realized, a frame region can be decreased in size compared to the configuration in which the sealing member is provided as in the electro-optic device disclosed in JP-A-2008-59868. Thus, it is possible to prevent the curving or distortion of the counter substrate due to the non-uniformity of the thickness of the sealing member and the thickness of the resin material.
Incidentally, in the configuration of the electro-optic device disclosed in JP-A-2007-157606, the resin material adhering and fixing the counter substrate to the light-emitting elements is considered to be preferably a low-viscosity material having good fluidity to form a surface coming into contact with the counter substrate as a flat surface as much as possible by alleviating unevenness on the light-emitting elements caused due to partition walls or the like. However, when the resin material has low viscosity, wet-spreading occurs up to a range more than necessary before the applied resin material is hardened, and thus for example, there is a problem that a defect such as overlapping of the resin material with a terminal section may occur.
Conceivable solutions to the above-mentioned problem include, for example, a method of applying and hardening a resin material covering the light-emitting elements to form a first resin layer and subsequently applying a resin layer between the first resin layer and the counter substrate to adhere both of the first resin layer and the counter substrate with a second resin layer so that the volume of the resin material applied once is decreased and the degree of wet-spreading is suppressed to be small. However, since the low-viscosity resin material is used in the first resin layer covering at least the light-emitting elements, there is a problem that it is difficult to remove the wet-spreading of the resin material when the first resin layer is formed. Also, since a difference occurs in the degree of the wet-spreading of the resin material depending on an elapsed time after the application of the resin material, there is also a problem that a variation occurs between individual devices.
In particular, when a process is performed on a large-scale mother substrate (element substrate) from which a plurality of electro-optic devices can be obtained, the elapsed time until hardening is different between the initially disposed resin material and the subsequently disposed resin material at the time of formation of the first resin layer on the mother substrate. Therefore, there is a concern that a variation occurs in the wet-spreading, and thus a shape may be different between the formed first resin layers. Then, there is a problem that pressure applied between the substrates may not be uniform, bubbles may be generated between the first resin layer and the second resin layer, or a variation may occur in the wet-spreading of the second resin layer when the mother substrate is adhered to the counter substrate by the second resin layer.